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Early Computer Games

In the 1950s, scientists would occasionally create a game as a demonstration, a research aid, or a training exercise, but these programs were usually short on interactivity and not intended primarily for entertainment. Tennis for Two can be considered an exception to this general rule, but even it was quickly dismantled after being played by a few hundred visitors to the Brookhaven National Laboratory. The academic and military-industrial research communities working on their batch processing computers were simply not interested in entertainment. And this attitude was perfectly understandable: with a computer representing a multi-million dollar investment, there was simply no time to waste on frivolous pursuits and no way to create a viable entertainment platform for use by the general public.

But at MIT in the late 1950s, something new was emerging in Building 26: an interactive computing environment accessible by nearly anyone affiliated with the university. The exploits of Kotok, Samson, and friends on the TX-0 birthed a new class of skilled computer users more interested in having fun than in performing actual research. This fun did not generally include games on the TX-0, which was still somewhat limited in speed and display capability, but these hacks laid the groundwork for the more advanced interactive programs to come. When the PDP-1 computer arrived at MIT in 1961, the TX-0 hackers were prepared to take their exploits to the next level. The result was the creation of the first (relatively) widespread and influential computer game, Spacewar!

Every monograph written on the history of the video game from Leonard Herman’s Phoenix to Tristan Donovan’s Replay has at the very least mentioned Spacewar!, and most of them discuss the creation of the game in depth and give it pride of place as the the game that truly launched the computer game phenomenon and influenced some of the earliest commercial products in the field. These accounts are largely drawn from just two sources: Stephen Levy’s book Hackers: Heroes of the Computer Revolution, for which the author interviewed most of the principle players in the MIT hacking scene, and an article Spacewar! co-creator J. Martin “Shag” Graetz wrote for Creative Computing magazine in 1981 entitled “The Origin of Spacewar.” As such, there is little disagreement between the principle sources on the inspiration for and the development of the game. Still, there are a few minor aspects of the narrative that have become muddled over time, which I will point out in my summary below.

Hacking the PDP-1

Some of the key contributors to the TX-0 and PDP-1 hacking scene at a Computer Museum event in 1984.

Even before the PDP-1 had formally arrived at MIT, the TMRC hackers began planning new coding exploits. According to Levy, Kotok learned about the machine’s impending installation while working a summer job at Western Electric in New Jersey and resolved to translate the debugger originally written by Jack Dennis as FLIT and then modified by others to become micro-FLIT to the new computer so that the hackers would have a superior programming environment the moment the PDP-1 came online. Peter Samson gave the new debugger the name DDT (both FLIT and DDT were pesticides, so the names were meant as puns related to “debugging”). As on the TX-0, the hackers wanted to build an improved assembler as well, but Dennis was perfectly happy with the default assembler that had been created by Bolt, Bernake & Newman. Kotok therefore made a deal with Dennis: if the hackers could create a new assembler over a single weekend, Dennis would pay them for their time on behalf of the university. Late one Friday in September, Kotok, Samson, Saunders, Wagner, and two others began frantically coding. By Monday morning, the assembler was done.

Like the assembler and debugger, much of the hacking done on the PDP-1 by TMRC consisted of extensions to existing hacks on the TX-0. One of the more impressive programs came from Samson, who converted his music program to the new machine. The original program on the TX-0 could only play a single voice, but the new program took advantage of the extended audio capabilities of the PDP-1 to create three-part harmonies. This feat of ingenuity so impressed DEC that the company actually made it freely available to its customers. Steve Piner, another TMRC member who matriculated to MIT in 1958, and Peter Deutsch, a precocious local teenager who joined the TX-0 and PDP-1 hacking crowd, developed a text editing program they called “Expensive Typewriter.” Another interesting hack allowed the TMRC members to serially link the PDP-1 and the TX-0 so that inputs made on one computer would also appear on the other. This hack played a role in a practical joke in which the TMRC programmers claimed to have an amazing new chess AI running on the PDP-1. In actuality, the “computer” was a person inputting commands on the attached TX-0. This was apparently the closest the TMRC hackers got to creating an actual game on the computer, as they remained focused on other areas of programming. However, a separate group of computer enthusiasts only tangentially affiliated with TMRC were brainstorming their own ideas on how best to exploit the capabilities of the PDP-1, and they were looking to create a more interactive experience.

ConceivingSpacewar!

Stephen “Slug” Russell, father of Spacewar!

In early 1961, three men in their mid twenties named Wayne Wiitanen, J. Martin Graetz, and Stephen Russell were working in the Littauer Statistical Laboratory at Harvard University, MIT’s close neighbor in Cambridge. According to an interview I conducted with Wiitanen, he and Graetz — called “Shag” due to his propensity for telling shaggy dog stories — became friends as freshmen at MIT in 1953, first meeting through the MIT Outing Club and quickly drawn together by a mutual interest in both rock climbing and playing music. Awarded a scholarship for his freshman year, Wiitanen subsequently lost his financial aid the next year, forcing him to find a new source of income. This led to a part time job at the Datamatic Corporation, the joint Raytheon-Honeywell computer company, in the Spring of 1955, where Wiitanen learned to program for the first time on an IBM 650. The next year, Wiitanen took a work-study job with the MIT Office of Statistic Services. Scheduled to graduate in Spring 1957, Wiitanen never completed a required senior thesis, but his computer experience landed him a job in the MIT Meteorology Department that Summer. After six months of compulsory military training in early 1958, Wiitanen took a job at the MIT Electronics Systems Laboratory before taking the job at Littauer in 1959.

According to Wiitanen, he and Graetz moved into a men’s cooperative called Old Joe Clark’s in the fall of 1957, where Graetz concentrated on various writing projects while Wiitanen worked for MIT. In 1959, Graetz and Wiitanen moved into an apartment at 8 Hingham Street in Cambridge, which they referred to as the “Hingham Institute” — a play on MIT’s common nickname, “The Institute.” It was during this period that Graetz became interested in Wiitanen’s work for the Meteorology Department and began paying attention to computers. According to an interview I conducted with him, Graetz, a native of Omaha, Nebraska, had been a chemistry major at MIT, but harbored no real love for the field and ultimately failed to graduate. After leaving the school, Graetz briefly pursued work as a chemistry lab technician at both his alma mater and Massachusetts General Hospital before Wiitanen arranged for him to be hired by Littauer as a junior operator feeding punched cards into the lab’s IBM 704 computer. He later became a program librarian while also immersing himself in the inner workings of the 704 and learning both assembly language and FORTRAN. According to Wiitanen, Russell was hired by the lab as a program consultant soon after, and the three men shared an office there.

According to Graetz in his Creative Computing article, he, Wiitanen, and Russell spent their idle hours working their way through the Lensman and Skylark novels of E.E. “Doc” Smith and going to local theaters to watch the latest B-movies released by Toho Studios of Japan. Doc Smith was a writer of trashy science fiction novels active in the 1920s and 1930s who laid the foundation for the “space opera” genre with his tales of intergalactic war and romance full of melodramatic dialogue, sudden plot twists, and cliched struggles between good and evil. The Toho movies, meanwhile, featured thin plots, extensive special effects, and numerous explosions as monsters like Godzilla and Rodan terrified Tokyo. Graetz and his friends dreamed of taking the space operas of Smith and adapting them as movies featuring Toho-style special effects.

According to our interview, in summer 1961 Graetz was dismissed from Harvard and called up his friend Jack Dennis, who secured him a job working on a diagnostic program for a new magnetic tape unit for the TX-0 at MIT. When the PDP-1 arrived that fall, he was just as eager as anyone else to begin programming on the machine. He therefore enlisted the Hingham Institute to brainstorm how best to demonstrate the capabilities of the PDP-1 through their own hack. They wanted to create a demo like the Whirlwind bouncing ball or the TX-0 HAX routine that highlighted the computer’s monitor, but they did not feel that either of those programs really demonstrated their respective computers particularly well because they did not tax the computer to its limits or fully engage the user in a pleasurable activity. According to Graetz, it was Wiitanen who finally articulated that action and the need for skilled user input would result in a particularly engaging demo and suggested flying spaceships around the screen as part of a race, contest, exploration, or fight. According to Wiitanen, this seminal moment came over tea at the Hingham Institute one afternoon and was not inspired by anything more particular than a general love of science fiction and a desire to make good use of the PDP-1 computer. Thinking back to their ambitions to create a Skylark movie, Graetz and Russell immediately honed in on the concept of a space conflict. Regrettably, despite coming up with the initial idea, Wiitanen was unable to participate in its implementation. An army reservist, when the Berlin Wall crisis flared in October 1961, Wiitanen was called up to active duty. Responsibility for implementing the demo, which the trio named Spacewar!, therefore fell to Hingham Institute compatriot Steve Russell.

According to an oral history he participated in with the Computer History Museum, Stephen “Slug” Russell was born in Hartford, Connecticut, to a mechanical engineer father and teacher mother. When Stephen was three, the Russell family embarked on a cross-country train excursion to visit his mother’s family in Washington state, which began a life-long fascination with trains. Model railroads soon became an obsession, which led him to become interested in electronics around the age of ten so he could create more elaborate model railroads. Soon after, his father was laid off and moved the family to Washington, where Russell attended high school. During this period, Russell became more deeply immersed in electronics through surplus World War II radio and radar equipment.

Russell beheld his first computer, Howard Aiken’s Harvard Mark I, as a teenager during a trip back east to visit his uncle, Harvard professor George Pierce. A firm believer that everyone should receive a proper education, Pierce later paid Russell’s tuition so he could attend Dartmouth College. While Dartmouth did not have a computer in those days, Russell did work with IBM tabulating equipment. During his senior year, he fell in with Professor John McCarthy, one of the pioneers in the field of artificial intelligence. When McCarthy moved to MIT in 1958, Russell followed to help implement a new programming language called LISP specifically tailored for AI research. Preoccupied by his AI work, Russell never completed a senior thesis at Dartmouth and therefore did not officially graduate. With his passion for trains, Russell joined TMRC in 1960 and became active in the S&P committee. He did not, however, become involved in the TX-0 programming scene, as he was too busy trying to implement LISP on the 704 in the Computation Center. By 1961, Russell was burned out on LISP and took the job at Harvard that led to his involvement with the Hingham Institute.

There is considerable confusion in the secondary video game literature regarding the relationship of Russell, Graetz, and Wiitanen to both MIT and the hackers of TMRC. Replay, for instance, identifies all three as TMRC members, while All Your Base Are Belong to Us describes the game as being written by Steve Russell and “his MIT engineering friends,” Phoenix refers to Russell as a graduate engineering student at MIT, and The Ultimate History of Video Games refers to Russell as “a fairly new Model Railroader who had just transferred from Dartmouth College.” In truth, none of these descriptions are completely accurate. Russell was certainly not a graduate student at MIT, for he is quite clear in his oral history that he never graduated from Dartmouth. He was not an employee at the time he was creating Spacewar! either, as both his oral history and Graetz’s article place him at Harvard in early 1961 after leaving his AI work at MIT. Graetz claims in Creative Computing that Russell did return to MIT in Fall 1961, but in Russell’s own oral history he gives a rundown of this period and appears to indicate he went straight from Harvard to Stanford in 1962 without any other stops in between. This contention is further supported by a 1963 article about computing at Stanford in Datamation that states Russell “worked under McCarthy at MIT and was brought to Stanford from Harvard,” and by a deposition given by John McKenzie in 1975 in which he stated Russell was at Harvard during the period of time he was creating Spacewar! While he was briefly a TMRC member as demonstrated by the organization’s membership roles and comments in his oral history, he explicitly states in his oral history that he did not become involved in the TX-0 hacking scene. Graetz, meanwhile, did work at MIT, but he has never claimed an affiliation with TMRC and his name cannot be found in the organization’s membership roles. Finally, Wiitanen was never at MIT at all, called to active duty before the PDP-1 hacking exploits could even begin. While TMRC was not directly involved in the conception of Spacewar!, however, its members would still play a critical role in moving the program from concept to playable game.

Building Spacewar!

Dan Edwards (l) and Peter Samson playing Spacewar! c. 1962

Despite no longer being an MIT employee, Russell continued to frequent Building 26 at the university and was therefore in a position to both observe and interact with the PDP-1 when it finally arrived. In his own recollection of the genesis of Spacewar! in his oral history, Russell remembers being particularly inspired to create the program by the “Minskytron,” a graphical demo recently created by professor Marvin Minsky in which three dots were generated on the screen that subsequently began to move around and interact with each other. Based on initializing constants entered by the user, these dots could form a variety of patterns from complex geometric shapes to fireworks effects. Russell’s exposure to the Minskytron and his interest in the new DDT debugger inspired him to implement the previously brainstormed Spacewar! hack on the PDP-1. As Graetz remembers, however, Steve did not acquire the name “Slug” for nothing, as he was generally loathe to start a new project if he could come up with a good excuse to put it off. Therefore, while the game concept took shape in the summer and fall, by December Russell had still not done any programming.

At this point, TMRC made its first critical contribution to Spacewar! As he describes the situation in his own Computer History Museum oral history, Alan Kotok practically served as a project manager as the program got off the ground, giving Russell encouragement and supplying him with bits of code taken from various libraries. As recounted by Graetz, Russell, and Levy, the critical moment came when Russell articulated what turned out to be his final excuse: he did not possess the sine-cosine routines required to place and move his ships around the screen. Kotok, by now considered the dean of the TMRC hacking community, enjoyed a good relationship with the engineers at DEC, so he took it upon himself to drive to the company headquarters in Maynard to hunt down the routines himself. When he returned to MIT and plopped them down in front of Russell, the hacker realized he had run out of excuses and set to work.

According to Levy, Russell finally began attacking the program in earnest in December 1961, but this date is almost certainly incorrect, as according to log files produced during the McKenzie deposition, the PDP-1 display was not installed until December 29, 1961, meaning he could not have even seen the Minskytron in action yet by December. Graetz recounts that Russell first succeeded in generating and moving a dot around the screen in January 1962. Initially worried that moving an entire ship would take too much processing power, Russell realized that since the points comprising the spaceship would always remain in the same relative position to each other, he only needed to calculate the angle once per frame and then implement code that rotated the entire grid as necessary. Before long, Russell had designed the two ships, which according to an interview excerpt with Russell in The Ultimate History of Videogames were designed to look like a curvy Buck Rodgers spaceship and a slender Redstone rocket. They soon gained the nicknames “Wedge” and “Needle” respectively.

According to Levy, by February 1962 Russell, with coding help from TMRC member Bob Saunders, had finished the basic program. (Note: In The Ultimate History of Video Games, Kent claims that Russell spent nearly six months creating the first version of the game, but this contradicts the primary sources, which all give the December to February time frame. It is possible Kent is referring to the total time from conception to implementation as opposed to just the time Russell actually spent programming or that he is including the time when additional modifications were made before the program’s public debut in May.) In this initial version, the two ships could accelerate, rotate clockwise, or rotate counterclockwise when the player flipped one of three toggle switches on the PDP-1. Flipping a fourth toggle switch allowed the player to fire torpedoes that would destroy the opposing ship if they made contact. Originally, there was a random chance that the torpedo would be a dud, but Russell changed them to be 100% reliable after negative user feedback. As explained by Russell to Kent, the game required two players due to a lack of computing power to craft an AI opponent.

A drawing of one of the custom control boxes crafted by the TMRC hackers to play Spacewar!

While Russell finished the basic Spacewar! program in February, there were significant modifications made over the next three months. As Levy recounts in Hackers, the TMRC programmers had by this time developed what he termed the “Hacker Ethic,” which was basically a philosophy that access to computers and tools for discovering how the world works should never be restricted and imperfect systems should always be improved by whomever has the ability to do so. This was essentially a transfer of the sensibilities of the TMRC S&P committee, which was full of students who loved taking things apart to see how they functioned and constantly strove to improve the track layout housed in Building 20 with their own inventive solutions. This “Hacker Ethic” would continue to be a driving force behind the evolution of computer technology for decades and still manifests today in the vibrant game modding communities, the continuing development of open source computer programs, and online collaborative projects like Wikipedia. In the case of Spacewar!, the Hacker Ethic insured that other members of the TMRC hacker community approached Russell with their own suggestions to improve the game. While some assume that TMRC members added these additions directly to the program themselves as part of the Hacker Ethic’s call for taking the initiative in improving computer programs, Norbert Landsteiner, who runs one of the most comprehensive Spacewar!webpages on the Internet, has painstakingly deconstructed and analysed the game’s code and concluded that Russell himself continued to serve as the gatekeeper for new features and incorporated them into his code in an orderly fashion.

The earliest modifications to Spacewar! were applied to the backdrop for the game. As Graetz recounts, Russell realized early in development that without any background objects, it was impossible to tell how the two ships were moving relative to each other when they were travelling at slow speeds. Russell solved this problem by including random dots of light on the screen that represented a star field. This inelegant solution did not satisfy Peter Samson, who decided to extract data from the American Ephemeris and Nautical Almanac to recreate the night sky between 22 1/2 ° N and 22 1/2 ° S down to the fifth order of magnitude. Not only was this routine capable of panning across the screen to display most of the best-known constellations in proper relation to each other, but by controlling the number of times the electron beam fired at any particular spot on the screen, Samson was also able to recreate the relative brightness of each star in the night sky. In the tradition of previous hacks on the TX-0, Samson dubbed his routine “Expensive Planetarium.” According to the game code itself as relayed by Landsteiner, Samson completed Expensive Planetarium around March 13, 1962, and Russell incorporated the code into the next formal release of the game, Spacewar! 2B, on April 2, 1962. (Note: In Replay Donovan appears to indicate that there was no background star field before Samson added Expensive Planetarium, but the primary sources agree that Samson’s contribution was replacing random dots with accurate constellations rather than incorporating background stars in the first place.)

A second critical innovation came from Dan Edwards, a graduate student and TMRC member who, like Russell, worked with John McCarthy on LISP. According to Graetz, Edwards was nonplussed by the lack of strategy in the game, which tended to devolve into the players wildly shooting at each other while zipping across the screen. He believed introducing gravity into the game would provide the necessary strategic depth, but Russell felt making the necessary modifications was beyond his abilities. Edwards therefore implemented the gravity himself, adding a sun to the middle of the screen and modelling its effects on the movement of the ships. This addition actually pushed the display beyond its limits and led to flickering, so Edwards looked for other places he could save resources. He quickly discovered that the program examined the ship lookup table to redraw each ship on each frame, a method Russell had initially used — according to his oral history — so that the shape of the ships could be easily changed on the fly. Edwards created a compiler that consulted the tables at the start of each game instead. This freed up the necessary runtime to incorporate the effect of gravity on the spaceships, but not on the torpedoes, which continued to travel in a straight line right through the sun. Russell and company decided these were “photon torpedoes” that were not affected by gravity to provide an in-game explanation for this effect.

The final significant modification to the game, patched in sometime in April or early May, was a hyperspace function developed by Graetz in which the player could flip a toggle switch to have his coordinates randomly scrambled so he would reappear somewhere else on the screen. According to Levy, this was a concept directly borrowed from Doc Smith and his spaceships that could use a “hyper-spatial tube” to enter “Nth space.” The idea, according to Graetz’s article, dated back to the early brainstorming sessions and was designed to introduce a last ditch panic button, but one that was not completely reliable so as not to be overpowered. In the initial version by Graetz, the player could only enter hyperspace three times, and it was possible to land right in the middle of the sun or end up in a similarly compromising position. This made hyperspace something a player would only want to use as a last resort.

Midway through development, the Spacewar! hackers also made an important quality of life change to the hardware itself. Tired of sore elbows and aching backs from hunching over the PDP-1 display flicking toggle switches — not to mention the constant threat of hitting the wrong switch and aborting the game and the visual advantage always held by one player due to the monitor being off to one side of the control panel — Alan Kotok and Bob Saunders decided to rectify the situation by creating their own custom control devices. According to Graetz, their first preference was for a joystick, but in 1962 the technology was still not common and proved to be unavailable to the hackers. Instead, the duo scrounged around the TMRC rooms for random bits of wood, wire, bakelite, and switching equipment and fashioned them into control boxes. The final result consisted of two levers and a button mounted in a wooden case with a bakelite top. One lever controlled rotation (pushing the lever to the left rotated the ship counterclockwise while pushing it to the right rotated the ship clockwise), the other lever controlled acceleration and hyperspace (pulling the lever towards the player accelerated the ship while pushing it away from the player activated hyperspace), and pressing the button fired torpedoes. With these control boxes, installed according to logs provided during the McKenzie deposition on March 19, 1962, both players could sit comfortably in front of the screen while also becoming more adept players due to the more logical control layout. Essentially, Kotok and Samson invented the first gamepads, an indispensable part of every video game system to come.

Spreading Spacewar!

A black-and-white screenshot of Spacewar! showing the two ships in their opening positions

In May, 1962, Spacewar! made its public debut at the annual MIT Science Open House. According to Graetz, the game was modified for that occasion to incorporate a scoring system to better limit individual sessions, while a larger CRT was also hooked up to the computer to facilitate spectator viewing of matches. Development on the game stalled over the next few months — possibly because Steve Russell was in the middle of a six month stint in the United States Army that he briefly discusses in his oral history — before what could be considered the “final” version of the original game was promulgated by Russell on September 24, 1962. Referred to as Spacewar! 3.1, this version incorporated certain functions that had previously been patched in like the scoring mechanic and hyperspace into the core game logic alongside several minor tweaks.

The same month Spacewar! made its public debut at MIT, Graetz presented a paper to the newly formed Digital Equipment Computer Users’ Society (DECUS), a support group for businesses and organizations using DEC computers that both conducted technical conferences and facilitated the exchange of software between members via magnetic tape, outlining the basic parameters of the game. From there, Spacewar! began to spread across the country. How quickly this spread occurred has recently been the subject of some debate. The traditional narrative, borrowed from Graetz’s article, posits a fairly rapid and widespread adoption of the game. In truth, more recent in-depth research by historians Marty Goldberg and Devin Monnens indicates that the game spread in fits and starts and did not really hit its stride until the late 1960s and early 1970s, when CRT terminals began to supplant teletypes as the primary user input. Nevertheless, it is fair to say that in an era when most game programs were one-offs that remained confined to a specific system, or at the very least a particular geographic area, Spacewar! penetrated computer labs from Cambridge to California, inspiring would-be programmers to follow the hacker ethic by creating their own variations on the game or even creating their own original programs. This activity culminated in the early 1970s in the creation of the first arcade video games — which were directly inspired by Spacewar! — and the subsequent launch of a new video game industry.

The main hubs of Spacewar! activity appear to have primarily formed around MIT hackers who brought the game directly to other institutions. The most important of these hubs was undoubtedly Stanford University, where Steve Russell ended up working in 1962 when he followed John McCarthy to the institution, who had grown frustrated with the lack of progress in AI research at MIT therefore decided to continue his work at Stanford. Spacewar! made the trip to the West Coast with Russell and became an immediate smash success, with a 1963 article in Datamation reporting that system administrators at Stanford had banned playing the game during business hours because its overwhelming popularity placed too much strain on system resources. Every time McCarthy’s research team received a more advanced computer, it received a Spacewar! port, keeping the game relevant among the computer-using crowd at the university for at least a decade. Indeed, in October 1972 Stanford became the site of what may have been the first organized video game tournament, the “Intergalactic Spacewar Olympics.” This event was famously chronicled by Stewart Brand for the December 1972 issue of Rolling Stone Magazine, giving Spacewar! a cultural cachet rare for computer games of the period. Furthermore, it was through Stanford that Bill Pitts and Nolan Bushnell, the originators of the first two arcade video games, were both first exposed to the landmark program that directly inspired their creations. (Note: I am aware that Mr. Bushnell claims to have first seen Spacewar! at the University of Utah, but that is a story for another blog post.)

Perhaps the best documented Spacewar! hub after MIT and Stanford is the University of Minnesota, where an MIT alum named Albert Kuhfeld programmed the game on a CDC 3100 computer in the Department of Physics and Astronomy that was being used in tandem with a new particle accelerator. According to interviews conducted by Landsteiner for his website and Goldberg and Monnens for their paper, Kuhfeld began programming the game soon after the computer arrived in 1966 because he missed his Spacewar!-playing days at MIT, but he was not able to do much actual programming until 1967. By 1969, the game was essentially complete. According to Goldberg and Monnens, the main differences between “Minnesota Spacewar” and the MIT version were the inclusion of timers for torpedoes, retro rockets for deceleration, and the “Minnesota Panic Button,” which activated a cloaking device. According to Landsteiner, Kuhfeld took a cue from MIT and fashioned control boxes for his version as well, with one lever for left/right, one lever for acceleration/deceleration, a button for torpedoes, and a switch for hyperspace/invisibility. A second control box replaced the movement buttons with a joystick. According to Goldberg and Monnens, Kuhfeld’s game normally had to be played during the day rather than at night, when the accelerator was often running, and could therefore only be played rarely at first. Eventually, more computer hardware was added to the lab, allowing playing time to increase and the game to become more popular. In July 1971, science fiction magazine Analog published an article about the game submitted by Kuhfeld himself, which, like the Rolling Stone article by Brand, helped raise Spacewar!‘s national profile.

Beyond MIT, Stanford, and Minnesota, evidence of Spacewar! distribution and popularity becomes increasingly sketchy and anecdotal. According to Goldberg and Monnens, the game spread quickly to other Boston-area institutions with PDP-1 computers and migrated to at least a few institutions farther afield like the University of Michigan, where the game arrived sometime between 1964 and 1966. This spread was at least partially aided by DEC itself. Because the game had been created specifically to use every last ounce of processing power the PDP-1 could bring to bear, DEC recognized that the program was a perfect poster child for the capabilities of the system. In 1963, DEC created a promotional brochure for the PDP-1 based around Spacewar! that highlighted the impressive number of calculations per second the computer performed to run the game as well as the complexity inherent in plotting the position of the ships and stars and modelling the Newtonian physics present in the game.

According to most sources, DEC further helped the spread of Spacewar! by eventually including it as a test program with every PDP-1 computer sold. The claim, as related by Levy and parroted by numerous sources thereafter, is that because the program used virtually every function of the PDP-1, it was a perfect final diagnostic program for the engineers at DEC before shipping a computer to the end user. Because the computer was then shipped without the memory being wiped, the game would run the first time the computer was turned on at its final destination, exposing yet another computer lab to the game. While this claim makes for a good story, however, it has yet to be confirmed by DEC primary sources. The best we have is the brochure already referenced above, which does prove that at the very least DEC ran demos of the game for potential buyers, and a statement by DEC engineer Gordon Bell to Goldberg that the story sounds plausible, but that he cannot confirm it. Martin Graetz also stated this claim in a 2007 Gamasutra article, but by that point the story had become so widespread that he may not have been speaking from first-hand knowledge. Indeed, his 1981 Creative Computing article is silent on this issue. Even if this story is true, Goldberg and Monnens caution that of the 55 PDP-1 computers sold, only about twenty were ever equipped with a display, and not all of these were equipped with one right out of the box. Therefore, even if this story is true, this method of distribution probably had a relatively limited impact, especially considering that the most important hub at Stanford was not established in this manner.

As the Datamation and Rolling Stone articles cited above demonstrate, Spacewar! became immensely popular on the Stanford campus, inspiring marathon playing sessions and intense competition among players. Goldberg and Monnens indicate, however, that response may have been more muted at other institutions. While the duo have only limited anecdotal evidence at their disposal, discussions with former players at both Harvard and the University of Michigan indicate that only a few people at either institution showed any interest in the game in the late 1960s. Still, the vibrant playing communities at MIT and Stanford coupled with slow yet steady migration to other computer labs across the country still make Spacewar! the first landmark program in video game history. Despite reaching a larger audience than any computer game to come before it, however, it still ultimately remained confined to university computer labs and entertained a relatively small portion of the U.S. population. As Russell told Kent, the hackers briefly toyed with the idea of making money on the game, but in 1962 it was still not possible to create a system cheap enough to qualify as a consumer product. It would require nearly another decade of innovation in computer technology and solid-state components before a commercial video game could finally become a reality.

Before World War II, MIT had not been much of a digital computer hotspot. While Howard Aiken at neighboring Harvard and John Atanasoff at Iowa State College were exploring digital solutions to solving complex differential equations, MIT remained firmly planted in the analog world with Vannevar Bush’s differential analyzer. During the war, however, the university became one of the primary centers for war-related scientific research. From the development of fire control systems at the Servomechanisms Laboratory to the breakthroughs in radar delivered by the Radiation Laboratory, MIT secured its place in the military-industrial complex as a critical research hub and became deeply involved in digital computer design through Projects Whirlwind and SAGE.

As Project Whirlwind gathered steam in 1950, MIT provost Julius Stratton formed a committee chaired by physics professor Philip Morse to study the question of whether and how MIT should introduce a computer for general use by faculty and staff at the university. In 1954, the committee returned a recommendation that MIT should build a Computation Center on campus “to aid faculty in keeping up to date on computer use within their fields and to assist them in introducing the use of computers into their courses; to educate all MIT students in computer use; and to explore and develop new ways of using computers in engineering and scientific research.” (Source: Guide to the Records of the Massachusetts Institute of Technology Computation Center) After considering whether to re-purpose the Whirlwind I or invest in a commercial machine, Morse decided in July 1955 to recommend MIT acquire an IBM 704 computer — which he managed to convince the company to provide free of charge, but would not be ready until 1957. Formally announced on September 23, 1955, the Computation Center was incorporated into the forthcoming Building 26 as an 18,000 square foot area near the northwest corner of the building dedicated solely to housing the 704 computer. (Source: A Century of Electrical Engineering and Computer Science at MIT, 1882-1982 by Karl Wildes and Nilo Lindgren) The center came online with the installation of the 704 in 1957 just as a new generation of college students that had received limited exposure to computers in the mid-1950s matriculated to MIT bound and determined to learn everything they could about the new machines. The interaction of these students with MIT’s new computing resources ultimately resulted in the creation of the first widely disseminated computer game.

The Tech Model Railroad Club

Alan Kotok (seated right with glasses), TMRC member and early computer hacker

In September 1946, a group of 26 students (according to the membership rolls maintained by TMRC on its website) established a new organization on the MIT campus called the Tech Model Railroad Club (TMRC). Located in Building 20, which had been built during World War II to house the Radiation Laboratory, TMRC dedicated itself to building and operating what quickly became an immense model railroad system. As discussed in Stephen Levy’s book Hackers: Heroes of the Computer Revolution, this work attracted two distinct types of students: the train and modelling buffs that would meticulously construct accurate railroad cars and elaborate scenery, and the electrical engineering buffs of the Signals and Power (S&P) Subcommittee that would constantly update and refine a track control system of impressive complexity described by Levy as appearing like “a collaboration between Rube Goldberg and Wernher von Braun.” Spending long hours together under the train layout installing parts donated by Western Electric or scrounged from Eli Heffreon’s junkyard in nearby Somerville, members of the S&P quickly bonded over shared interests and even developed their own lexicon. For example, a person who studied instead of joining in the fun was called a “tool,” garbage was called “cruft,” and a clever project undertaken just for the fun of it was called a “hack.” Ultimately, this group of tinkerers would launch the computer revolution referenced in the title of Levy’s book.

Hackers paints portraits of the key TMRC members that matriculated to MIT in 1958. Foremost among them were Alan Kotok and Peter Samson. According to Levy, Kotok grew up in the New Jersey suburbs of Philadelphia, where his parents learned he was an electrical engineering prodigy when he was already building and wiring lamps by the time he was six years old. As touched on in Hackers and elaborated on in an oral history Kotok conducted with the Computer History Museum, Kotok’s first exposure to a computer was a high school field trip to a Socony-Mobil research laboratory in Paulsboro, NJ (Note: Hackers claims the facility was in nearby Haddonfield, but Kotok’s contention in his oral history that it was in Paulsboro appears to accurate), where the students not only viewed a mainframe computer, but actually ran through a programming exercise using punched cards. From that day forward, Kotok knew his future lay with computers, which is why he applied to MIT. Interested in model railroads, Kotok quickly gravitated to TMRC, where according to Levy he was quickly accounted one of the best electrical engineers in S&P.

Samson, on the other hand, was a local boy who grew up just thirty miles away from the university in Lowell, Massachusetts. His first exposure to computers was a television program on the Boston public TV channel WGBH that gave a basic introduction to computer programming. Inspired, he learned everything he could about computing and actually tried to build his own computer using relays pried out of pinball machines. He also viewed computers on trips to MIT, where he resolved to continue his education after high school. Samson joined TMRC on the first day of Freshman orientation in Fall 1958 and was instantly hooked when he beheld the complex system of wires, relays, and switches that kept the track running. TMRC members received their own key to the club room after putting in forty hours on the layout: Samson earned his key in less than three days.

From available evidence, it appears few TMRC upperclassmen shared the same interest in computers as the class of 1962. One that did was Bob Saunders, who joined TMRC in 1956 and by 1958 had become the president of the S&P Subcommittee. Unlike Kotok and Samson, Saunders appears not to have received exposure to computers before matriculating to the school. Levy does describe several engineering exploits he undertook as a boy in the suburbs of Chicago, however, including the construction of a six-foot-tall high-frequency transformer that Saunders claimed blew out television reception for miles around and working a summer job at the phone company installing central office equipment. Indeed, it was the telephone parts used in the train control system that first attracted Saunders to TMRC.

Samson, Kotok, and several other TMRC students gained exposure to the IBM 704 in the Computation Center in Spring 1959 through the first computer course MIT had ever offered to Freshmen, and Kotok even became intimately involved in a chess project being implemented on the computer (and which will be discussed in detail in a later post), but Levy recounts that this experience did not satisfy the bright and curious TMRC members. As a batch processing computer, the 704 required trained IBM staff to actually run programs and provided little feedback to the students and professors who would bring their punched cards to Building 26 and return hours later to see the results, all the while hoping no serious errors had prevented the program from running. Levy, echoing the words of Ted Nelson in his seminal 1974 work Computer Lib, compared these interactions to acolytes (the programmers) asking for divine aid from a fickle god (the computer) through a dedicated priesthood (the operators). This metaphor of a computer priesthood remains an oft-invoked image to this day when discussing batch processing mainframes. Frustrated by their limited access to the 704, TMRC students searched for alternative means to scratch their computing itch.

As described by Levy, Peter Samson particularly enjoyed stalking the hallways of Building 26 at all hours looking for new activities to feed his insatiable curiosity. He would trace wiring, examine telephone switching equipment, and look for unguarded technology to fiddle with. One of these excursions led him to the Electronic Accounting Machinery (EAM) room in the basement, where the university had installed several IBM accounting machines, including an IBM 407. These were electromechanical tabulators of limited capability, but they could read and sort cards and print out the results. Even better, they were only guarded during the day, making the 407 the closest thing to a computer to which TMRC members could secure direct access. Before long, Samson and other TMRC members could be found clustered around the 407 late into the night using the machine to keep track of the expanding array of switches under their train layout and seeing just how far they could push the technology. This work on the 407 represented one of the earliest manifestations of a new computer-centric culture within TMRC.

Hacking the TX-0

Jack Dennis, the former TMRC member and MIT professor that introduced TMRC to the Tx-0

In July 1958, Lincoln Laboratory decided it had no further need for the TX-0 computer built by Ken Olsen and Wes Clark and therefore placed it on semi-permanent loan to MIT, which housed it in the Research Laboratory of Electronics (RLE) in Building 26, located, according to Levy, just one floor above the 704 in the Computation Center. As the computer was coming online, a new MIT instructor by the name of Jack Dennis was just settling into his office down the hall. An MIT alum, Dennis, according to a TX-0 retrospective in the Spring 1984 issue of the Computer Museum Report, had recently completed his dissertation and accepted the instructor position in the fall of 1958, but he was uninterested in pursuing his dissertation topic further. Dennis was soon drawn to the nearby TX-0 and began writing programs for the computer, the most important of which were FLIT, a debugger he wrote with Thomas Stockham, and MACRO, an assembler. These programs allowed a programmer to work in assembly language rather than the more difficult machine language and more easily identify and correct bad code, therefore opening TX-0 programming to a larger user base. About a year and a half after the TX-0 arrived, Dennis was placed in charge of the machine.

Unlike the 704 in the Computation Center, which was operated by trained staff, the TX-0 was generally available for faculty and graduate student research: all a person needed to do was sign up for a block of time. Jack Dennis, however, wanted to go a step further. As an undergraduate, Dennis had the opportunity to program on the Whirlwind, and he believed that interested undergraduate students were a valuable resource that should be encouraged to run their own computer experiments. Dennis had also joined TMRC as a freshman in 1949 and still had contacts within the group, so he knew exactly where to go to recruit his cadre of interested programmers. In his oral history, Alan Kotok remembers Dennis approaching TMRC members in Fall 1958 and asking if they would like to learn to program the TX-0. He took aside an interested group of students that included S&P president Bob Saunders and freshmen Kotok, Samson, Dick Wagner, and Dave Gross and delivered a crash course on the TX-0. The students were amazed to discover a computer that allowed them to program directly and fix their code on the fly. With Dennis’s support, they negotiated with the people in charge of the computer, Earl Pugh and John McKenzie, who agreed to allow them access to the computer during blocks of time not already committed to official research.

During the day, the TX-0 was usually being put to serious use, but few projects were ever run overnight. Therefore, the TMRC members became nocturnal creatures, ignoring both their classes and any semblance of a social life to maximize the amount of time they could spend programming the machine. The young coders derived great joy from pushing the computer to its limits and mastering its capabilities. Like the work they did on the railroad in building 20, the projects they undertook on the TX-0 purely for the fun and the challenge came to be called “hacks,” and the programmers began referring to themselves as “hackers.”

Few of the programs created by the TMRC coders did anything useful — or at least nothing useful enough to justify employing a multi-million dollar computer. Hackers and the Computer Museum Report describe several of these programs.Peter Samson created a program to convert Arabic numbers to Roman numerals and then puzzled out a way to manipulate the primitive built-in audio speaker to play simple, single-voice melodies using a square wave. Kotok discovered a way to interface an FM receiver with the analog-to-digital converter on the computer to create a program he called the Expensive Tape Recorder, while Wagner, who had been using an electro-mechanical calculator in a numerical analysis class, was inspired to write a program called Expensive Desk Calculator.

The Demo Scene

A screenshot of an emulated recreation of MOUSE

In addition to the experiments of the TMRC hackers, the TX-0 also became home to a number of demos. As explained by J.M. Gratez in his August 1981 article for Creative Computing, “The Origin of Spacewar,” getting the general public interested in early computers was rarely easy. While many people were attracted by the high technology on display, they were soon bored watching a computer work, as there were no manifestations of its activity save for blinking lights and whirring tape. This quickly led programmers to create programs that were visually striking and/or interactive in order to generate interest in computer use. The previously discussed Bertie, NIMROD, MIDSAC pool, and Tennis for Two were all essentially interactive demos created for this purpose, and TX-0 programmers were soon crafting their own demos to achieve the same result.

The TX-0 demo programmers most likely took some inspiration from the program recognized as the earliest computer demo, a bouncing ball program created on the Whirlwind I by Charles Adams in 1950. As described by Graetz, this simple program began with a single dot falling from the top of the screen and bouncing when it hit the bottom of the screen, accompanied by a sound from the Whirlwind speaker. The ball would continue to bounce around all four sides of the screen until finally running out of momentum and rolling off through a hole in the floor. While the program was simple, the effect proved stunning in a time when no other computer could actually update a CRT display in real-time.

Graetz describes several demos on the TX-0. One, called HAX, would generate an ever-changing array of shapes to show off the capabilities of the TX-0’s CRT. Another was a Tic-Tac-Toe game — played against the computer by typing commands using the flexowriter — designed to show off the computer’s interactivity. Perhaps the most impressive hack, combining the visual interest of HAX and the interactivity of Tic-Tac-Toe, was the MOUSEprogram developed by Doug Ross and John Ward and first publicized in January 1959. As described in the Spring 1984 Computer Museum Report, Ward had observed people programming on the Whirlwind at Lincoln Labs but had never had the opportunity to program the machine himself. Therefore, when the TX-0 became available, he decided to sign up for time but did not know what type of program to write. Remembering a program he had developed while working with a UNIVAC 1103 on Eglin Air Force Base with Ross, the head of MIT’s Computer Applications Group and the person who first coined the term “computer-aided design” (CAD), Ward convinced Ross to help him create a similar program on the TX-0. In the finished product, with logic by Ross and a display by Ward, the user would create a maze directly on the CRT by erasing lines from an 8×8 grid of squares using the light pen and then place pieces of cheese throughout the maze. A mouse would then traverse the maze while eating all the cheese. The mouse would run out of energy if it did not reach a piece of cheese within a certain amount of time, but it would remember the paths taken in each attempt and therefore develop a more efficient route over time. A variant replaced the cheese with martini glasses and had the mouse stagger the more it drank.

MOUSE and Tic-Tac-Toe highlighted the potential of an interactive computer as a device for playing games, but the TX-0 display remained too limited to create a truly engaging interactive visual experience. In 1961, however, DEC donated one of the first PDP-1 computers to MIT, which was placed in the RLE in the room next to the TX-0. Sporting a more sophisticated display than the TX-0, the PDP-1 was the perfect platform for the TMRC hackers to take the lessons learned through programming the TX-0 to create the first truly influential computer game, Spacewar!

Before leaving the 1950s behind, we now turn to the most prolific computer game concept of the decade: chess. While complex simulations drove the majority of AI research in the military-industrial complex during the decade, the holy grail for much of academia was a computer that could effectively play this venerable strategy game. As Alex Bernstein and Michael de V. Roberts explain it for Scientific American in June 1958, this is because chess is a perfect game to build an intelligent computer program around because the rules are straightforward and easy to implement, but playing out every possible scenario at a rate of one million complete games per second would take a computer 10108 years. While this poses no real challenge for modern computers, the machines available in the 1950s and 1960s could never hope to complete a game of chess in a reasonable timeframe, meaning they actually needed to learn to react and adapt to a human player to win rather than just drawing on a stock of stored knowledge. Charting the complete course of the quest to create a perfect chess-playing computer is beyond the scope of this blog, but since chess computer games have been popular entertainment programs as well as platforms for AI research, it is worth taking a brief look at the path to the very first programs to successfully play a complete game of chess. The Computer History Museum presents a brief history of computer chess on its website called Mastering the Game, which will provide the framework for most of this examination.

According to scholar Nick Montfort in his monograph on interactive fiction, Twisted Little Passages (2005), credit for the first automated chess-playing machine goes to a Spanish engineer named Leonardo Torres y Quevedo, who constructed an electro-mechanical contraption in 1912 called El Ajedrecista (literally “the chessplayer”) that simulated a KRK chess endgame, in which the machine attempted to mate the player’s lone king with his own king and rook. First demonstrated publicly in 1914 in Paris and subsequently described in Scientific American in 1915, El Ajedrecista not only calculated moves, but actually moved the pieces itself using a mechanical arm. A second version constructed in 1920 eliminated the arm and moved pieces via magnets under the board instead. Montfort believes this machine should qualify as the very first computer game, but a lack of any electronics, a key component of every modern definition of a computer game — though not a requirement for a machine to be classified as an analog computer — makes this contention problematic, though perhaps technically correct. Regardless of how one chooses to classify Quevedo’s contraption, however, it would be nearly four decades before anyone took up the challenge of computer chess again.

Turochamp and Machiavelli (1948)

Alan Turing, father of computer science and computer chess pioneer

As creating a viable chess program became one of the long-standing holy grails of computer science, it is only fitting that the man considered the father of that field, Alan Turing, was also the first person to approach the problem. Both the computer history museum and Replay state that in 1947 Turing became the first person to write a complete chess program, but it proved so complex that no existing computer possessed sufficient memory to run it. While this account contains some truth, however, it does not appear to be fully accurate.

As recounted by Andrew Hodges in the definitive Turing biography Alan Turing: The Enigma (1983), Turing had begun fiddling around with chess as early as 1941, but he did not sketch out a complete program until later in the decade, when he and economist David Champernowne developed a set of routines they called Turochamp. While it is likely that Turing and Champerdowne were actively developing this program in 1947, Turing did not actually complete Turochamp until late 1948 after hearing about a rival chess-playing program called Machiavelli written by his colleagues Donald Michie and Shaun Wylie. This is demonstrated by a letter Hodges reprinted in the book from September 1948 in which Turing directly states that he had never actually written out the complete chess program, but would be doing so shortly. Copeland also gives a 1948 date for the completion of Turochamp in The Essential Turing.

This may technically make Machiavelli the first completed chess program, though Michie relates in Alan M. Turing (1959), a biography written by the subject’s own mother, that Machiavelli was inspired by the already in development Turochamp. It is true that Turochamp — and presumably Machiavelli as well — never actually ran on a computer, but apparently Turing began implementing it on the Ferranti Mark 1 before his untimely death. Donovan goes on to say that Turing tested out the program by playing the role of the computer himself in a single match in 1952 that the program lost, but Hodges records that the program played an earlier simulated game in 1948 against Champerdowne’s wife, a chess novice, who lost to the program.

Programming a Computer for Playing Chess, by Claude Shannon (1950)

Claude Shannon (right) demonstrates a chess-playing automaton of his own design to chess champion Edward Lasker

While a fully working chess game would not arrive for another decade, key theoretical advances were made over 1949 and 1950 by another pioneer of computer science, Claude Shannon. Shannon was keenly interested in the chess problem and actually built an “electric chess automaton” in 1949 — described in Vol. 12 No. 4 of the International Computer Chess Association (ICCA) Journal (1989) — that could handle six pieces and was used to test programming methods.

His critical contribution, however, was an article he wrote for Philosophical Magazine in 1950entitled “Programming a computer for playing chess.” While Shannon’s paper did not actually outline a specific chess program, it was the first attempt to systematically identify some of the basic problems inherent in constructing such a program and proffered several solutions. As Allen Newell, J.C. Shaw, and H.A. Simon relate in their chapter for the previously mentioned landmark AI anthology Computers and Thought, “Chess-Playing Programs and the Problem of Complexity,” Shannon was the first person to recognize that a chess game consists of a finite series of moves that will ultimately terminate in one of three states for a player: a win, a loss, or a draw. As such, a game of chess can be viewed as a decision tree in which each node represents a specific board layout and each branch from that node represents a possible move. By working backwards from the bottom of the tree, a player would know the best move to make at any given time. This concept, called minimaxing in game theory, would conceivably allow a computer to play a perfect game of chess every time.

Of course, as we already discussed, chess may have a finite number of possible moves, but that number is still so large that no computer could conceivably work through every last move in time to actually play a game. Shannon recognized this problem and proposed that a program should only track moves to a certain depth on the tree and then choose the best alternative under the circumstances, which would be determined by evaluating a series of static factors such as the value and mobility of pieces — weighted based on their importance in the decision-making process of actual expert chess players — and combining these values with a minimaxing procedure to pick a move. The concept of evaluating the decision tree to a set depth and then using a combination of minimaxing and best value would inform all the significant chess programs that followed in the next decade.

Partial Chess-Playing Programs (1951-1956)

Paul Stein (seated) plays chess against a program written for the MANIAC computer

The complexities inherent in programming a working chess-playing AI that adhered to Shannon’s principles guaranteed it would be nearly another decade before a fully working chess program emerged, but in the meantime researchers were able to implement more limited chess programs by focusing on specific scenarios or by removing specific aspects of the game. Dr. Dietrich Prinz, a follower of Turing who led the development of the Ferranti Mark 1, created the first such program to actually run on a computer. According to Copeland and Diane Proudfoot in their online article Alan Turing: Father of the Modern Computer, Prinz’s program first ran in November 1951. As the computer history museum explains, however, this program could not actually play a complete game of chess and instead merely simulated the “mate-in-two problem,” that is it could identify the best move to make when two moves away from a checkmate.

In The Video Game Explosion, Ahl recognizes a 1956 program written for the MANIAC I at the Los Alamos Atomic Energy Laboratory by James Kister, Paul Stein, Stanislaw Ulam, William Walden, and Mark Wells as the first chess-playing program, apparently missing the Prinz game. Los Alamos had been at the forefront of digital computing almost from its inception, as the lab had used the ENIAC, one of the first Turing-complete digital computers, to perform calculations and run simulations for research relating to the atomic bomb. As a result, Los Alamos personnel kept a close watch on advances in stored program computers in the late 1940s and early 1950s and decided to construct their own as they raced to complete the first thermonuclear weapon, colloquially known as a “hydrogen bomb.” Designed by a team led by Nicholas Metropolis, the Mathematical Analyzer, Numerical Integrator, and Computer, or MANIAC, ran its first program in March 1952 and was put to a wide variety of physics experiments over the next five years.

While MANIAC was primarily used for weapons research, the scientists at Los Alamos implemented game programs on more than one occasion. According to a brief memoir published by Jeremy Bernstein in 2012 in the London Review of Books, many of the Los Alamos scientists were drawn to the card tables of the casinos of nearby Las Vegas, Nevada. Therefore, when they heard that four soldiers at the Aberdeen Proving Ground had published an article called “The Optimum Strategy in Blackjack” in the Journal of the American Statistical Association in 1956, they immediately created a program on the MANIAC to run tens of thousands of Blackjack hands to see if the strategy actually worked. (Note: Ahl and a small number of other sources allude to a Blackjack game being created at Los Alamos on an IBM 701 computer in 1954, but I have been unable to substantiate this claim in primary sources, leading me to wonder if these authors have confused some other experiment and the 1956 blackjack program on the MANIAC). Therefore, it is no surprise that scientists at the lab would decided to create a chess program as well.

Unlike Prinz’s program, the MANIAC program could play a complete game of chess, but the programmers were only able to accomplish this feat using a simplified 6×6 board without bishops. The program did, however, implement Shannon’s system of calculating all possible moves over two levels of the decision tree and then using static factors and minimaxing to determine its next move. Capable of performing roughly 11,000 operations per second, the program only played three games and was estimated to have the skill of a human player with about twenty games experience according to Shaw. By the time Shaw’s article was published in 1961, the program apparently no longer existed. Presumably it was lost when the original MANIAC was retired in favor of the MANIAC II in 1957.

The Bernstein Program (1957)

Alex Bernstein with his chess program in 1958

A complete chess playing program finally emerged in 1957 from IBM, implemented by Alex Bernstein with the help of Michael de V. Roberts, Timothy Arbuckle, and Martin Belsky. Like the MANIAC game, Bernstein’s program only examined two levels of moves, but rather than exploring every last possibility, his team instead programmed the computer to examine only the seven most plausible moves, determined by operating a series of what Shaw labels “plausible move generators” that identified the best moves based on specific goals such as king safety or prioritizing attack or defense. After cycling through these generators, the program picked seven plausible continuations and then made a decision based on minimaxing and static factors just like the MANIAC program. It did so much more efficiently, however, as it considered only about 2,500 of over 800,000 possible permutations. Running on the faster IBM 704 computer, the program could handle 42,000 operations per second, though according to Shaw the added complexity of using the full 8×8 board rendered much of this speed advantage moot and the program still took about eight minutes to make a move compared to twelve for the MANIAC program. According to Shaw, Bernstein’s program played at the level of a “passable amateur,” but exhibited surprising blind spots due to the limitations of its move analysis. It apparently never actually defeated a human opponent.

The NSS Chess Program (1958)

Herbert Simon (left) and Allan Newell (right), two-thirds of the team that created the NSS program

We end our examination of 1950s computer chess with the NSS chess program that emerged from Carnegie-Mellon University. Allan Newell and Herbert Simon, professors at the university who consulted for RAND Corporation, were keenly interested in AI and joined with a RAND employee named Cliff Shaw in 1955 to fashion a chess program of their own. According to their essay in Computers and Thought, the trio actually abandoned the project within a year to focus on writing programs for discovering symbolic logic proofs, but subsequently returned to their chess work and completed the program in 1958 on the JOHNNIAC, a stored program computer built by the RAND Corporation and operational between 1953 and 1966. According to an essay by Edward Feigenbaum called “What Hath Simon Wrought?” in the 1989 anthology Complex Information Processing: The Impact of Herbert A. Simon, Newell and Shaw handled most of the actual development work, while Simon immersed himself in the game of chess itself in order to imbue the program with as much chess knowledge as possible.

The resulting program, with a name derived from the authors’ initials, improved upon both the MANIAC and Berstein programs. Like the Bernstein program, the NSS program used a combination of minimaxing, static value, and a plausible move generator to determine the best move to make, but Newell, Simon, and Shaw added a new important wrinkle to the process through a “branch and bounds” method similar to the technique that later researchers termed “alpha-beta pruning.” Using this method, each branch of the decision tree was given a maximum lower and a minimum upper value, alpha and beta, and the program only considered those branches that fell in between these values in previously explored branches. In this way, the program was able to consider far fewer moves than previous minimaxing-based programs, yet mostly ignored poor solutions rather than valuable ones. While this still resulted in a program that played at an amateur level, the combination of minimaxing and alpha-beta pruning provided a solid base for computer scientists to carry chess research into the 1960s.

So now we turn to the most discussed of all the 1950s computer games: Tennis for Two, designed by Willy Higinbotham and largely built by Robert Dvorak at the Brookhaven National Laboratory (BNL) in 1958. Unlike the games discussed previously, Tennis for Two was built specifically to entertain the public rather than just to demonstrate the power of a computer or train a group of students, giving it some claim as the first true computer “game” from a philosophical standpoint. That is certainly the contention of BNL itself, which dismisses NIMROD and OXO as programming demonstrations rather than entertainment. Ultimately, this debate matters little, as Tennis For Two only existed briefly and did not influence later developments in the industry.

While Tennis for Two did not inspire later designers, however, it did gain a new notoriety in the 1970s when lawyers for arcade companies defending against a patent lawsuit brought by Magnavox discovered the existence of the game and unsuccessfully attempted to portray it as an example of prior art that invalidated Ralph Baer’s television gaming patents. Higinbotham was called to testify on multiple occasions during various patent suits that continued into the 1980s, which is one reason the game is far better documented than most of its contemporaries. The game also received public recognition after Creative Computing ran a feature devoted to it in October 1982 because the magazine’s editor, David Ahl, had actually played the game at Brookhaven back in 1958. As a result of this article, Tennis for Two was considered the first computer game until more in-depth research in the late 2000s uncovered some of the earlier games listed in the previous post, and the early monographs such as Phoenix, High Score!, and The Ultimate History of Video Games accord the game pioneering status. Even though newer works like Replay and All Your Base Are Belong to Us acknowledge earlier programs, however, they continue to give Tennis for Two pride of place in the early history of video games due to it arguably being the first pure entertainment product created on a computer.

William A. Higinbotham

Before diving into the game itself, we should examine the man who created it. According to an unpublished account now hosted at the BNL site that he wrote in the early 1980s supplemented by a deposition he gave in 1985, William A. Higinbotham graduated from Williams College in 1932 with a bachelor’s degree in physics and spent eight years working on a Ph.D at Cornell that he ultimately abandoned due to a lack of money. Higinbotham first worked with an oscilloscope during a senior honor’s project at Williams and spent his last six years at Cornell working as a technician in the physics department, which gave him the opportunity to learn a great deal about electronics. As a result, he was invited to MIT in December 1940 to work on radar at the university’s Radiation Laboratory, where he concentrated on CRT radar displays. In December 1943, Higinbotham transferred to Los Alamos to work on the Manhattan Project, where he was quickly promoted to lead the electronics division and, according to Replay, worked on timing circuits. He left Los Alamos for Washington, DC, in December 1945, where he spent two years doing education and PR work for the American Federation of Scientists, a group that worked to stem nuclear proliferation. In 1947, he came to BNL, where he became the head of instrumentation in 1951 or 1952.

The above provides a solid overview of Higinbotham the scientist, but Harold Goldberg in All Your Base Are Belong to Us also gives us a portrait of Higinbotham’s less serious side. According to Goldberg, who drew his information from a profile in Parade, Willy was a natural entertainer who called square dances, played the accordion, and led a Dixieland band named the Isotope Stompers. He also exhibited a penchant for making technology fun, once attaching a sulky and two wagons to the family lawnmower so he could drive his kids around the yard. Seeing this side of the eminent physicist, its no surprise that he would find a way to make a computer entertaining as well.

The original Tennis for Two display

Higinbotham created Tennis for Two as a public relations vehicle. Every year, BNL held three visitor’s days in the fall — one each for high school students, college students, and the general public — in which the scientists gave tours of the facilities and built exhibits related to the lab’s work in the staff gymnasium. Most accounts of the exhibits emphasize that they consisted of unengaging static displays, but in his 1976 deposition for the first Magnavox patent lawsuit, Higinbotham states that the staff always tried to include something with “action,” though he does not specify whether this included games. Therefore, Higinbotham may not have been the first person to liven up the event through audience participation, but he was still definitely the first person that decided to entertain the public with a computer game.

As the BNL website and his notes indicate, Higinbotham was inspired to create Tennis for Two after reading through the instruction manual for the lab’s Donner Model 30, a vacuum tube analog computer. The manual described how the system could be hooked up to an oscilloscope to display curves to model a missile trajectory or a bouncing ball complete with an accurate simulation of gravity and wind resistance. The bouncing ball reminded Higinbotham of tennis, so he sketched out a system to interface an oscilloscope with the computer and then gave the diagram to technician Robert Dvorak to implement. Laying out the initial design only took Higinbotham a couple of hours, after which he spent a couple of days putting together a final spec based on the components available in the lab. Dvorak then built the system over three weeks and spent a day or two debugging it with Higinbotham. The game was largely driven by the vacuum tubes and relays that had defined electronics for decades, but in order to render graphics on the oscilloscope, which required rapidly switching between several different elements, Higinbotham and Dvorak incorporated transistors, which were just beginning to transform the electronics industry.

Tennis for Two‘s graphics consisted of a side-view image of a tennis court — rendered as a long horizontal line to represent the court itself and a small vertical line to represent the net — and a ball with a trajectory arc displayed on the oscilloscope. Each player used a controller consisting of a knob and a button. To start a volley, one player would use the knob to select an angle to hit the ball and then press the button. At that point, the ball could either hit the net, hit the other side of the court, or sail out of bounds. Once the ball made it over the net, the other player could either hit the ball on the fly or the bounce by selecting his own angle and pressing the button to return it. Originally, the velocity of the ball could be chosen by the player as well, but Higinbotham decided that three controls would make the game too complicated and therefore left the velocity fixed.

A modern recreation of the Tennis for Two controller

According to Higinbotham, Tennis for Two was a great success, with long lines of eager players quickly forming to play the game. Based on this positive reception, Higinbotham brought the game back in 1959 on a larger monitor and with more sophisticated gravity modelling that allowed the player to simulate the low gravity of the Moon or the high gravity environment of Jupiter. After the second round of visitor days, the game was dismantled so its components could be put to other uses. Higinbotham never patented the device because he felt at the time that he was just adapting the bouncing ball program already discussed in the manual and had created no real breakthrough. While he appears to have been proud of creating the game, he stated in his notes that he considered it a “minor achievement” at best and wanted to be remembered as a scientist who fought the spread of nuclear weapons rather than as an inventor of a computer game.

And now with all the introductions and definitions out of the way, it is finally time to start talking history. First, a note of caution. This post on computer games in the 1950s will at times refer to this or that program as the “first” to model a particular game or mechanic, but this should be read as the first that we know of rather than as an absolute statement of origination. While many interesting games from this time period have been unearthed — and in some cases even been recreated to play on modern hardware — the games of the 1950s were largely confined to research labs run by universities, large corporations, and national governments and were not intended for mass distribution and/or public consumption. As a result, there is a high degree of likelihood that researchers created logic puzzles, board games, card games, military simulations, etc., that never received larger exposure and have long since been lost. With that one caveat in mind, here is a look at the first decade of video gaming.

The first digital computers were completed in the early 1940s, but it would take nearly another decade for the first computer games to appear. A subsequent blog post will summarize the evolution of the mainframe in the 1940s and 1950s in more detail, but for the moment I will just say that the early computers were extremely few in number, tended to be dedicated to highly specific functions, were difficult to reprogram (if they could be reprogrammed at all), and lacked the capability to execute a stored program. Consequently, even if a researcher had felt a “simulation” or a “game” might have been useful in his work, there would have been little opportunity to create one. By the 1950s, however, computers had been commercialized and had become sophisticated enough to be set to a variety of tasks. As we shall see, one of those tasks was playing games.

The 1950s have largely been ignored by the monographs covering the history of video games. Phoenix, High Score!, and the Ultimate History of Video Games all skip the decade entirely with the exception of brief mentions of Tennis for Two, while the more recent All Your Base Are Belong to Us devotes a rather substantial prologue to that game, but again ignores most of the developments of the period. Only Tristan Donovan’s Replay and Mark Wolf’s The Video Game Explosion — through a chapter by David Ahl — cover the 1950s in any depth.

This omission is understandable for two reasons. First, the authors of these books are primarily interested in the growth of the video game as an entertainment product and pop culture phenomenon, while the majority of the programs from this period were research projects that were not made available to the general public. Tennis for Two actually served as a public spectacle, making it a more suitable topic for such a narrative. Second, because these projects stayed locked up in research labs and were usually dismantled or discarded when they had served their purpose, these early games usually did not spread beyond a few academics and therefore exerted little to no influence on subsequent games. Donovan and Ahl between them identify several games from this period, however, which I will now examine here.

Bertie the Brain (1950)

Entertainer Danny Kaye celebrates a victory over Bertie the Brain at the Canadian National Exposition in 1950

For the moment, Bertie the Brain, a custom-built computer financed by Rogers Majestic (a prominent vacuum tube manufacturer and one of the forerunners of Canadian media giant Rogers Communications), is the earliest known computer game actually implemented — although a small number of game programs may have been described and/or written earlier, most notably several early chess programs. (Note: The development of computer chess over the 1950s is a long enough tale on its own and will therefore be covered in its own blog post.) Unlike most subsequent games in this post, Bertie was not a research project, but was intended specifically to impress the public as to the potential of computers.

Bertie grew out of a project at the University of Toronto to build an early mainframe computer, the University of Toronto Electronic Computer, or UTEC. One of the earliest university-led electronic computer projects, UTEC design commenced in 1948, and a prototype was completed in 1950. The project was ultimately abandoned, however, when the university decided to purchase a computer from British firm Ferranti — a pioneering computer maker described in more detail below — instead.

One critical member of the UTEC team was a University of Toronto Ph.D. candidate named Josef Kates. According to a profile on Bertie written by Chris Bateman for Canadian magazine Spacing in August 2014, Kates was born into a large Austrian Jewish family in 1921, but fled Nazi persecution in 1938, ultimately winding up in the United Kingdom. Kates enlisted in the British Army as an optician’s apprentice, but on the outbreak of World War II he was shipped to an internment camp in Canada due to his nationality. Finishing high school in New Brunswick, Kates eked out a living cutting wood, sewing socks, and repairing fishing nets until his previous lens experience landed him a job with Imperial Optical in 1941. He soon moved to Rogers Majestic to build radar tubes before joining the UTEC project after the war.

One of Kates’s key contributions to the project was a device he devised in 1949 called the Additron, an electron tube that was smaller, less complex, and less power-hungry than the typical vacuum tubes of the day. The Additron ultimately never found its way into the UTEC nor did it enter mass production, as by the time a long and difficult patent process concluded in 1956, the technology was already obsolete. Rogers wanted to promote the technology during this delay, however, so Kates proposed creating a Tic-Tac-Toe game using Additron tubes for display at the Canadian National Exhibition (CNE).

Unveiled at the CNE in the summer of 1950, Kates’s machine, dubbed “Bertie the Brain,” stood just over thirteen feet high and consisted of a custom-built computer, a lighted keypad for the player to input his move, and a lighted panel that showed the layout of the board and announced the winner. Once the player entered his move, Bertie countered nearly instantaneously and was virtually unbeatable, at least on the highest difficulty. Kates would often turn down the difficulty for children and then crank it back up for adults. The machine proved immensely popular, but it was dismantled at the end of the exhibition after serving its purpose.

Bertie the Brain is not discussed in any video game history monograph written to date, but why it has been overlooked is not exactly clear. It was heavily publicized at the time, with Life Magazine even running a feature on Bertie that involved famed entertainer Danny Kaye challenging the machine and finally winning after the difficulty had been turned down multiple times. Kates himself went on to a long and distinguished career in the Canadian scientific community, and at least one newspaper article discussing his appointment to a new post written in 1975 referenced the creation of the game. A 2001 monograph by John Vardalas entitled The Computer Revolution in Canada: Building National Technological Competence also devotes a paragraph to the game. The recent article in Spacing has brought new attention to the game and its inventor, however, so this omission will hopefully be corrected in the future.

NIMROD (1951)

An artist’s rendering of NIMROD as it would have appeared at the Berlin Industrial Show

With Bertie so far overlooked by the various monographs written about video game history, Donovan and Ahl both identify the NIMROD, a custom-built computer from British engineering firm Ferranti, as the first computer game. Like Bertie, NIMROD was built to impress upon the public the great potential of computers.

Ferranti has the distinction of being one of the oldest companies to become involved in the nascent computer industry after World War II. According to a timeline made available by the Museum of Science and Industry in Manchester, Siemens engineer Sebastien de Ferranti established the company in 1882 to market a dynamo (an early electrical generator) of his own design. By the early twentieth century, Ferranti had become one of the most important power companies in the United Kingdom and was instrumental in the establishment of a national power grid. Defense work during and after World War II in fields ranging from gun sights to radar to guided missiles led naturally into first electronics and then computers, culminating in the launch of the Ferranti Mark 1 in 1951. While the UNIVAC I from Remington Rand is often identified as the first commercially available computer (see, for example About.com), the first UNIVAC I was delivered in June 1951 (Source: University of Pennsylvania, though some sources also claim the commercial deal was struck as early as March 31), while the first Ferranti Mark 1 was delivered to the University of Manchester in February (Source: University of Manchester School of Computer Science), making it the first commercially available computer by a matter of months (if we want to get really technical, the BINAC computer delivered to Northrop in 1949 was the first commercially sold computer, but it was a one-off unlike the Ferranti and Univac computers that were produced in quantity and made available to any interested party).

According to Donovan, who apparently drew most of his material from the personal website of one Peter Goodeve, Ferranti found itself in a difficult position in late 1950: the company had promised to exhibit a computer at the upcoming Festival of Britain, but proved unable to honor the commitment. The Festival had been conceived by deputy prime minister Herbert Morrison as a “tonic for the nation” to demonstrate to the people of the United Kingdom that the art, technology, and ingenuity of the British people would heal the gaping wounds still remaining from the horror of World War II and help lead the world into a better tomorrow, making this an important public relations event for Ferranti. An Australian engineer named John Bennett who had worked on the pioneering EDSAC computer in the late 1940s ultimately provided a solution: Ferranti should demonstrate the mathematical capabilities of the modern computer and the fundamentals of computer programming to the public by displaying a custom-built machine that played the strategy game nim. According to Donovan, Bennett was inspired by the Nimatron, an electro-mechanical contraption displayed by Westinghouse at the 1940 World’s Fair. Donovan appears to have drawn this claim from a 2001 German article linked at Mr. Goodeve’s website. While this is a logical claim for the article to make, the author does not provide any proof from primary sources. Bennett himself appears to be silent on this point, at least in this excerpt from his autobiography.

Again from Donovan and Goodeve, the NIMROD was built by Raymond Stuart-Williams between December 1950 and April 1951 and first exhibited at the festival on May 5, 1951. After the festival ended, the NIMROD was displayed for three weeks in October at the Berlin Industrial Show and subsequently dismantled. Lacking a monitor, the NIMROD used a series of lights as a display, which represented the individual pegs of the game. The human player chose which “pegs” to remove by pressing the corresponding buttons on a control panel situated in front of the machine. While NIMROD gave the public one of its first opportunities to play a game on and against a computer, Bennett was, in his own words, more interested in demonstrating programming algorithms and principles than in entertaining anyone. As such, neither Bennett nor Ferranti followed up on this ground-breaking machine.

Checkers Programs (1951-1952)

Christopher Strachey’s Draughts Program on the Ferranti Mark 1

Although not mentioned by Donovan or Ahl, it appears that a checkers program created by Englishman Christopher Strachy may well be the first computer game executed in software to run on a Turing-complete computer — in contrast to the custom hardware of Bertie and NIMROD. This program’s significance extends far beyond the realm of computer games, however, as it may have also been the first program of any kind to exhibit artificial intelligence (AI). According to a biography hosted by the IEEE Computing Society, Strachey was a mathematician and physicist serving as a master at Harrow School in 1951 when he was introduced to the Pilot ACE computer at Britain’s National Physical Laboratory (NPL). As a programming exercise to familiarize himself with the machine, Strachey created a draughts game (checkers to Americans), taking inspiration from an article in the June 1950 issue of Penguin Science News written by NPL physicist Donald Davies called “A Theory of Chess and Naughts and Crosses.”

In The Essential Turing (2004), a collection of Alan Turing’s papers compiled by B.J. Copeland, Copeland writes that Strachey completed a preliminary version of his program by May 1951 and first tried to run it on the Pilot ACE in July, but was unsuccessful due to program errors. According to the IEEE Paper, that same month Strachey traveled to the University of Manchester to see the first Ferranti Mark 1 and consult with Turing, who had recently completed a Programmers’ Handbook for the machine. According to Copeland, Turing’s encouragement was crucial in Strachey finally getting the draughts program in working order on the Mark 1. According to an article by David Link entitled “Programming ENTER: Christopher Strachey’s Draughts Program” that appeared in issue 60 of Resurrection, the official publication of the Computer Conservation Society, the game was finally completed in July 1952. That same year, Strachey described his game at a computer conference in Toronto, which, according to Copeland, directly inspired a programmer named Arthur Samuel to create his own version.

Arthur Samuel playing with his checkers program

An electrical engineer with a master’s degree from the Massachusetts Institute of Technology (MIT), Arthur Samuel was one of the more important pioneers of AI research in the United States. According to an article penned by John McCarthy and hosted by the Stanford Artificial Intelligence Laboratory, Samuel experienced his first brush with computing at the relatively early date of 1946 when he joined a team at the University of Illinois that began an ultimately unsuccessful project to build an electronic computer. According to McCarthy, it was during this project that Samuel first conceived of writing a checkers program that could defeat a champion player of the game to show just how powerful a tool a computer could be. In 1949, Samuel accepted a job at IBM’s Poughkeepsie Laboratory, where he was part of the team that designed the landmark IBM 701 computer. He remained at the company until retiring from the corporate world in 1966.

According to Copeland, it was Strachey’s presentation in 1952 that rekindled Samuel’s interest in devising a checkers program, and indeed it was near the end of that year that Samuel completed an initial version on the 701, which Copeland surmises was the first AI program created in the United States. As related by both Copeland and Donovan, Samuel continued to refine this program over the next several years and accomplished a major milestone in 1955 when the program became capable of analyzing its own play and learning from its mistakes. As the program continued to gain notoriety, it was actually demonstrated on national television on February 24, 1956 (Source: IBM100, a centennial website created by IBM). According to McCarthy, IBM stock rose 15 points on the back of this demonstration.

In Replay, Donovan claims that by 1961 Samuel’s program was “defeating US Checkers champions,” but this claim is exaggerated. According to McCarthy, in 1961 Samuel answered a call for submissions to the first anthology devoted to AI research, Computers and Thought, with a paper describing his checkers program. The editors of the collection, Ed Feigenbaum and Julian Feldman, suggested that Samuel include an account of his program’s best game as part of the article, so Samuel decided to challenge a champion player to a match. McCarthy states that the chosen player was “the Connecticut state checker champion, the number four ranked player in the nation,” but alas this also appears to be an exaggeration. The IBM 100 website identifies the player, one Robert W. Nealey, as a “self-proclaimed checkers champion.” Further digging shows that Mr. Nealey was indeed a checkers player from Connecticut, but his champion status derived from a tournament for blind chess players held in Peoria, Illinois, in which he claimed the title of “world blind checker champion” by default when no one else showed up to compete (Source: St. Petersburg Times February 26, 1980). Therefore, while the program, now running on an IBM 7094, did win its match against Nealey in 1962, this was not as impressive a victory as Donovan and McCarthy make it sound. Indeed, according to a webpage devoted to Samuel’s program maintained by the Department of Computing Science at the University of Alberta, Nealey actually won a rematch the very next year, while the program later lost eight out of eight games against two actual world-class checkers players at a world championship match held in 1966.

Early Simulation Games (1952-1958)

The Air Defense Direction Center replica constructed by RAND Corporation for “Project Simulator”

Unlike the purely civilian research projects above, computer games simulating complex systems and interactions originated almost entirely within the military-industrial complex, which already had a long history of war gaming and systems simulation that predated computers. As this blog is focused on games created for entertainment rather than training, I will largely avoid discussing military and defense contractor projects, but I feel an overview of the earliest such games is appropriate as part of tracing the origins of computer gaming generally.

In the Video Game Explosion, Ahl identifies the earliest military simulations as coming out of the RAND Corporation beginning in 1952. According to the company’s own website, Project RAND — short for “Research ANd Development” — originated as an outgrowth of advanced weapons research conducted during World War II and began in December 1945 as a collaboration between the Douglas Aircraft Company and the United States Army Air Forces (USAAF). As explained in RAND and the Information Evolution (2008) by Willis Ware, USAAF commander General “Hap” Arnold recognized that some of the most important military advances of World War II had been the result of collaboration between the military, academia, and industry, and therefore felt a joint project like RAND that was not completely under military control was essential to carrying this spirit of collaboration forward. In 1948, the newly established US Air Force chose to spin the project out as its own non-profit corporation.

RAND employed mathematicians and scientists across a wide array of disciplines and contributed numerous breakthroughs in fields ranging from artificial intelligence to networking to space travel, but for now we turn our attention to the organization’s Systems Research Laboratory. As related in a RAND paper from October 1956 by F.N. Marzocco entitled The Story of SDD, the Systems Research Laboratory was the brainchild of RAND consultant John Kennedy, a psychologist who believed that RAND could not fully understand the impact of technology on the modern battlefield without also studying the “human factors” present in any interaction between man and machine. At Kennedy’s recommendation, RAND established the laboratory in May 1951 to undertake such studies, staffing it with a mix of psychologists and mathematicians.

At the time of the lab’s foundation, RAND’s Electronics Division was expending a great deal of energy on the Air Force’s Air Defense System, a network of radar stations that would feed data on incoming aircraft to a series of Air Defense Direction Centers (ADCCs) where personnel would compile data, evaluate threats, and scramble interceptors as necessary to protect the integrity of US air space. With the Cold War entering its nuclear phase, perfecting the country’s Air Defense System was vital to insure long-range Soviet bombers could be intercepted before delivering a nuclear payload on American soil. According to Ware, Kennedy and his colleagues, most notably Robert Chapman, William Biel, Bogusław Boghosian, and Milton Weiner, were particularly interested in cognitive learning and how best to train organized groups that were required to coordinate their activities to carry out a larger task. As such, they were naturally drawn to the ADDCs and with the encouragement of Melvin Kappler of the Electronics Division chose as their first major study “Project Simulator,” an ADDC computer training program.

According to Marzocco, the Systems Research Laboratory constructed a nearly exact physical replica of the ADDC located in Tacoma, Washington, along with partial replicas of three associated early warning stations. Ware relates that the system was constructed in a warehouse at 4th and Broadway in Santa Monica and was based around an IBM 701 that would run a simulation of incoming aircraft that the trainees had to identify, pinpoint, and interdict. The display consisted of a faux radar screen drawn by an IBM 407 printer that produced a new paper readout each time the radar changed. Marzocco tells us that the first exercise using the system, code-named “Casey,” ran from February 4 to June 8 1952 and involved twenty-eight students from UCLA. A second run, code-named “Cowboy,” followed in early 1953 with actual military personnel.

According to Ware, the Air Force was so pleased by the initial results of Project Simulator that it decided to deploy the system across the service and funded a variety of improvements such as a high resolution camera from Mitchell Camera Company and a cathode ray tube (CRT) display for the 701 from IBM so a film strip could replace the paper readouts of the original system. According to Marzocco, RAND responded to the growing scope of the project by establishing a new System Training and Programming Division (quickly shortened to System Development Division) under Kappler in September 1955 to deploy the training system, which now went by the name “System Training Project” (STP). By May 1956, the division had installed the STP at seven Air Divisions. In December 1957, the division was spun off as its own corporation, System Development Corporation (SDC). While the STP appears to be the first military simulation run primarily by a computer, it cannot really be classified as a complete computer game, as the 701 merely plays the film and traces flight paths over a two-hour training session. A human team was apparently still required to actually administer the exercise and interpret the results.

The Army, meanwhile followed the lead of the Air Force in establishing a research think tank in 1948, the Operations Research Office (ORO), which operated as an adjunct to Johns Hopkins University. Researchers at ORO created what may have been the first true computer war game, Hutspiel. According to a 1964 technical report by Joseph Harrison, Jr. entitled Computer-Aided Information Systems for Gaming, Hutspiel was a 1955 theater-level war game written for an analog computer called the Goodyear Electronic Differential Analyzer (GEDA) intended to study the use of tactical nuclear weapons and conventional air support in Western Europe in the event of a Soviet invasion. In this game, which built on previous GEDA simulations devoted to exercises such as allocating artillery and missile fire among competing targets, one player would control NATO forces in France, Belgium, and West Germany, while the other player would control a Soviet force attempting to penetrate the region across a frontage of roughly 150 miles. At the start of the game, each player would allocate his forces across the sectors he controlled and choose targets for his planes and nukes, which could consist of enemy troops, airfields, supply depots, and transportation facilities. GEDA would then determine the results. In the original version of the game, the simulation would continue without human intervention until a player paused to issue new orders, but in subsequent versions the game was divided into turns of fixed time increments. While the game modeled both reinforcement and resupply, it did not model troop movement other than by rail, nor did it account for weather and terrain. By 1964, the Research Analysis Corporation, an organization founded to continue the work of the ORO after the Army terminated its contract with Johns Hopkins in 1961, was working on a more complex version of Hutspiel called Theaterspiel that ran on an IBM 7094 computer. (Note: In The Video Game Explosion, Ahl incorrectly attributes Hutspiel to the Research Analysis Corporation, which did not yet exist in 1955.)

Military simulation projects also led directly to the first business simulation game. In the early 1950s, RAND Corporation developed a pen-and-paper simulation called MONOPLOGS in which the players would learn the principles of logistics by running a portion of the Air Force supply system. In October 1956, the company inaugurated a new Logistics Systems Laboratory to create computer simulations to train logistics personnel, the first of which was LP-I in 1957. Meanwhile, according to an article entitled “U.S. Wargaming Grows Up” by Sharon Ghamari-Tabrizi MONOPLOGS so impressed the American Management Association (AMA) that it assembled a team in 1956 that included consultants from both RAND and IBM to create a business management simulation called The Top Management Decision Simulation, which was programmed on an IBM 650 and delivered in May 1957. As with military simulations, the primary purpose of the early business simulations was training. As such these games quickly spread to business schools as evidenced by The Management Game, a 1958 program devised by Kalman Cohen, Richard Cyert, and William Dill at the Carnegie Institute of Technology in Pittsburgh — renamed Carnegie Mellon University in 1967 after a merger with the Mellon Institute of Industrial Research — that Ahl incorrectly identifies as the first business simulation (though it may have very well been the first one implemented in the classroom since the AMA game was targeted at current executives). According to Ahl, this game still sees use in business schools to this day — though as the CMU website points out it did receive a major overhaul in 1986 — and runs over the course of two semesters as the player takes control of one of three competing detergent companies and makes decisions over a three year period regarding everything from R&D to marketing. According to a 1962 article by Paul Greenlaw, Lowell Herron, and Richard Rawdon entitled “Business Simulation in Industrial and University Education,” there were already at least eighty-nine business simulations in use by the end of 1961

Early Graphical Games (1952-1954)

A recreation of the OXO display from a software emulator

To this point, I have examined several programs that first delivered entertainment and/or artificial intelligence to the world of mainframe computers, but little that puts the “video” in video game. This is because the computers of the 1950s were largely machines of punched cards, paper tape, and printed results, not display screens and CRTs. Perhaps the first computer game to render images on a display was OXO by Alexander Douglas, which he deployed in 1952. (NOTE: I have been unable to locate a source that gives the month in 1952 that Douglas implemented his program, so it is possible that the aforementioned draughts game by Strachey, completed in July, actually came first.)

While a doctoral candidate in mathematics at the University of Cambridge in 1952, Douglas decided to develop a thesis concerning human-computer interaction. (NOTE: Some sources claim that this research formed the basis of his dissertation, but a quick look at the catalog of the Newton Library at Cambridge shows this is not the case. The program was, however, described in the dissertation, which is why we have such complete knowledge of it today.) Needing a platform to test the theories of his thesis, Douglas chose to program a naughts and crosses (tic-tac-toe to Americans) game for the EDSAC computer at the University of Cambridge. As will be discussed later, the EDSAC represented a landmark in computer history that pioneered several innovations. For the purposes of this post, however, the most important advance was the machine’s ability to display a map of its memory on a CRT as a 35 x 16 dot matrix. (Source: “A Tutorial Guide to the EDSAC Simulator” by Martin Campbell-Kelly) This feature was primarily used to help debug programs, but could also be used to create images on the monitor by manipulating specific dots on the grid. Douglas took full advantage of this capability for OXO. To play the game, one used a rotary phone dial connected to the computer. Each space on the tic-tac-toe grid corresponded to one of the numbers on the dial, so the player simply dialed that number to make his mark.

A pool game created at the University of Michigan’s Willow Run facility on the MIDSAC computer

Both OXO and Strachey’s draughts program sported relatively static graphics to convey the current state of the game board, but a more dynamic graphical game soon emerged from the University of Michigan. One of the lesser known hotspots for computer research in the 1950s, the university developed several analog and digital computers at an offsite laboratory located at the Willow Run manufacturing complex. Established by the Ford Motor Company in 1941, Willow Run initially built aircraft components before producing roughly half of the B-24 Liberator bombers that flew in World War II. After the war, an airfield built as part of the complex passed to civilian control, and the University of Michigan established a research facility there. This lab became involved in computer research in aid of defense projects ranging from air traffic control systems to the BOMARC (Boeing-Michigan Air Research Center) guided missile.

According to a pamphlet by Norman Scott entitled “Computing at the University of Michigan: The Early Years Through 1960,” Willow Run built two digital computers in 1952, the Michigan Digital Automatic Computer (MIDAC) and the more advanced Michigan Digital Special Automatic Computer (MIDSAC). According to Scott, both computers were built by an engineer named John DeTurk and derived from the Standards Eastern Automatic Computer (SEAC) built by the National Bureau of Standards in 1950. According to the June 27, 1954, edition of the Chicago Tribune, the Willow Run facility publicly debuted the two computers for the first time on June 26, 1954, which were both programmed to play games for the occasion. The MIDAC hosted a craps game that declared its “box point” and then rolled simulated dice until it won or lost, with the results printed on an automatic typewriter attached to the machine. MIDAC also hosted a tic-tac-toe game that pitted a human against a hardware-controlled opponent. If a player attempted to cheat by placing multiple symbols on his turn, the computer would call him out for it.

Unlike MIDAC, MIDSAC was hooked up to a 13-inch CRT display, allowing it to host a far more impressive game. According to a deposition given by a research associate at the lab named William Brown, he and a colleague named Ted Lewis were approached by DeTurk to create a demonstration program for the forthcoming event in early 1954 and suggested a pool game because they were both avid players and felt some form of game would be particularly interesting for the audience. Developed over the course of roughly six months, the program simulated a standard pool table and a full rack of fifteen balls, which two players would take shots at by controlling a two inch cue stick. The controls consisted of a joystick, which moved the cue stick around the table, a knob, which rotated the cue stick to choose the angle of the shot, and a button to actually strike the cue ball. The program subsequently performed 25,000 operations a second to determine the speed, trajectory, and bounce of every ball as they collided with each other and the sides of the table. Any ball that entered a pocket would disappear. Due to limited processing power, the sides of the table and the pockets were not actually displayed on the CRT, but instead were drawn in grease pencil on a transparent overlay. According to both the Chicago Tribune article and Brown’s deposition, the graphics updated seamlessly and gave the illusion of continuous movement, making the MIDSAC pool game perhaps the first computer game to feature real-time graphics. Despite its pioneering features, however, this game has yet to appear in any monograph of video game history.

In his autobiography, Memoirs of a Computer Programmer (1985), EDSAC designer Maurice Wilkes briefly describes another early CRT game created on his pioneering machine by an enterprising programmer who manipulated the display to create a vertical fence with a single hole in it that the player could manipulate to appear on either the top half or bottom half of the screen. Periodically, a horizontal row of dots would appear and attempt to pass through the fence. If the hole was on the same half of the screen as the dots, they would pass through, otherwise they would retreat. Initially, the movement of the dots would be random, but the program was actually capable of learning so that if the player moved the hole according to a consistent pattern, the row of dots would eventually figure out the sequence and appear in the correct place every time. Wilkes provides no details on when this program was implemented nor who designed it, but he is quick to point out that “no one took this program very seriously.” This once again reinforces the idea that 1950s computer researchers like John Bennett and Alexander Douglas might have occasionally found games useful to prove a point, but had no real interest in harnessing computers purely for entertainment. Indeed, there is only one known computer game created in the entire decade that was designed specifically to entertain the public rather than test or demonstrate computer theories or train students and personnel, and it will be the subject of my next post.